Premium
Flexibility in the P2 domain of the HIV‐1 Gag polyprotein
Author(s) -
Newman John L.,
Butcher Eric W.,
Patel Dipti T.,
Mikhaylenko Yelena,
Summers Michael F.
Publication year - 2004
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.04614804
Subject(s) - human immunodeficiency virus (hiv) , domain (mathematical analysis) , flexibility (engineering) , virology , computational biology , chemistry , biology , mathematics , mathematical analysis , statistics
Abstract The HIV‐1 Gag polyprotein contains a segment called p2, located between the capsid (CA) and nucleocapsid (NC) domains, that is essential for ordered virus assembly and infectivity. We subcloned, overexpressed, and purified a 156‐residue polypeptide that contains the C‐terminal capsid subdomain (CA CTD ) through the NC domain of Gag (CA CTD ‐p2‐NC, Gag residues 276–431) for NMR relaxation and sedimentation equilibrium (SE) studies. The CA CTD and NC domains are folded as expected, but residues of the p2 segment, and the adjoining thirteen C‐terminal residues of CA CTD and thirteen N‐terminal residues of NC, are flexible. Backbone NMR chemical shifts of these 40 residues deviate slightly from random coil values and indicate a small propensity toward an α‐helical conformation. The presence of a transient coil‐to‐helix equilibrium may explain the unusual and necessarily slow proteolysis rate of the CA‐p2 junction. CA CTD ‐p2‐NC forms dimers and self‐associates with an equilibrium constant ( K d = 1.78 ± 0.5 μM) similar to that observed for the intact capsid protein ( K d = 2.94 ± 0.8 μM), suggesting that Gag self‐association is not significantly influence by the P2 domain.